Prevalence of Vitamin D Deciency and Its Associated Risk Factors Among Rural Population of the Northern Part of the Persian Gulf Maryam Marzban The Persian Gulf Tropical Medicine Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran Mohammadreza Kalantarhormozi Department of Endocrine and Metabolic Disease, the Persian Gulf Tropical Medicine Research Center, Bushehr University of Medical Sciences, Bushehr, Iran Mehdi Mahmudpour The Persian Gulf Tropical Medicine Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran Afshin Ostovar Osteoporosis Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran Saeed Keshmiri Faculty of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran Amir Darabi The Persian Gulf Tropical Medicine Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran Abdolmohammad khajeian Faculty of health, Bushehr University of Medical Sciences, Bushehr, Iran Amirreza Bolkheir The Persian Gulf Tropical Medicine Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran Azam Amini Department of Internal Medicine, Division of Rheumatology, School of Medicine, Bushehr University of Medical Sciences, Bushehr,Iran Iraj Nabipour ( [email protected] ) The Persian Gulf Tropical Medicine Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran Research Article Keywords: Vitamin D deciency, Prevalence, Rural, Enrichment, Iran Posted Date: November 25th, 2020 DOI: https://doi.org/10.21203/rs.3.rs-109364/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Page 1/11 Abstract Background: Accumulating evidence indicates that vitamin D deciency has been increased globally since the last two decades. However, the majority of these studies concerned on cities and there is scant information regarding the prevalence of vitamin D in rural areas. The main aim of this study was to investigate the prevalence of vitamin D deciency and its associated risk factors among rural population in Bushehr province which has the longest border with the Persian Gulf. Methods: The rural inhabitants with ≥25 years old from three mountainous, plain, and seashore areas of Bushehr province were selected through a stratied multi-cluster random sampling method. After obtaining the participants’ demographic and anthropometric data and their past medical history, serum 25- hydroxy vitamin D was measured using ELISA. Results: A total of 1806 (means±SD, 46.30± 14.22 years old) rural subjects (34.84% males and 64.88%) participated in this study. The prevalence of vitamin D deciency, insuciency and suciency were 27.87%, 50.39% and 21.74%, respectively. The deciency of vitamin D in women was higher than men (OR=1.27, 95% CI: 1.05 to 1.54, P=0.040). There was a positive signicant correlation between age and serum vitamin D levels. Men with vitamin D deciency had higher BMI (P=0.008); this association was not observed among women (P=0.74). There was no signicant difference between the food items consumption frequencies, and vitamin D status (P>0.05). The mountainous, and plain areas had the highest and lowest vitamin D levels, respectively. Conclusion: Although, Bushehr province is located in a sunny part of Iran, the prevalence of vitamin D deciency was high among its rural population. The shift of their life styles patterns and rapid industrialization in these rural areas may be responsible. Therefore, the enrichment of dietary sources with vitamin D and the use of vitamin D supplements are recommended to tackle the high prevalence of vitamin D deciency in the rural population of the northern part of the Persian Gulf. Introduction The deciency of vitamin D has been reported from all parts of the world, and there is a signicant association between low serum levels of vitamin D and communicable and non-communicable diseases [1]. Accumulating evidence has shown that vitamin D presents benecial effects on our tissues and organs. Beside this, the more vitamin D concertation means the less occurrence of cancer and the related mortalities. In addition, vitamin D deciency has signicant association with high blood pressure, type I diabetes, multiple sclerosis, rheumatoid arthritis , and other autoimmune diseases [2]. Although there is no consensus for dening, and optimal levels of serum 25-hydroxy vitamin D, vitamin D deciency has been dened at cut point serum levels of less than 20 ng/ml; because at this level, parathyroid hormone begins to increase. Hence this outpoint is considered the physiologic denition for vitamin D deciency [3]. Insucient sun light exposure, age- related decrease in vitamin D synthesis in skin, and low dietary intake are attributing factors for circulating levels of this vitamin. Therefore, vitamin D supplementation and sucient sun light exposure can protect most of the people from vitamin D deciency. Five to ten minutes of direct sun light exposure on the arms and legs between 10:00 AM to 3:00 PM during spring, summer, and autumn can prevent vitamin D insuciency [4]. Because of the signicant effect of vitamin D on bone mineral homeostasis, bone mineral density, and nally pick bone mass, several large multi-central interventional studies with vitamin D supplementation are under investigations in all over the world [5]. Even though there is a limited amount of vitamin D in plants, a sucient amount of vitamin D3 could be found in sh oil, calf of liver, cheese, and eggs yolk [6]. In addition, acute liver failure, nephrotic syndrome, renal disease, rickets and hyperparathyroidism could be considered as etiologies for vitamin D insuciency[7]. The geographical location, methods of skin coverage, skin color, and consumption of foods with lack of vitamin D are prominent causes for vitamin D insuciency[6]. In a survey study which was done on American population from 2001 to 2006 (National Health , and Nutrition Examination Survey), it was shown that 32 percent of participants had serum vitamin D level less than 20 ng/ml [8]. The studies in developing countries have shown that osteoporosis, increased risk of falling, and bone fracture were associated with an increase in the prevalence of vitamin D deciency [9]. Moreover, the past two decades studies elucidated a high prevalence of vitamin D deciency in China, Turkey, Saudi Arabia, and Iran which varied between 30 to 93 percent [10]. Page 2/11 Vitamin D deciency was reported in 75.1% of females and 72.1% of males from the Iranian Multi-Centric Osteoporosis Studies (IMOS). The result of this study was consistent with those results that had been reported with other studies from the Middle East region. [11]. A comprehensive epidemiological and ecological descriptive study on vitamin D status in Iran showed that the mean of vitamin D concentration was 25.4 ng/ml which was in the range of vitamin D deciency [12]. The high prevalence of vitamin D deciency among the Iranian population may be due to the shift of Iranian lifestyle patterns towards the urbanization and industrialized lifestyles resulting in low sunlight exposure that accentuates the low dietary intake of vitamin D in this country [11]. In addition, air pollution is an important affecting factor for vitamin D deciency in the large cities [13]. Although similar prevalence rates for vitamin D deciency in urban and rural areas of Asia have been reported, in some studies, the urban subjects in comparison to the rural subjects had more prevalence of vitamin D deciency [5]. In Iran, the majority of studies have been done in urban areas and capital cities [10, 14, 15]. There is a lack of information about the prevalence of vitamin D deciency and its serum levels in rural areas [10] Therefore, the limited information about vitamin D in rural areas may prevent to design strategies to combat vitamin D deciency in Iranian rural subjects who are rapidly changing their lifestyle towards urbanization and industrialization. Hence, this phenomenon may accelerate the situation of vitamin D deciency among this rural population. The aim of this study was to investigate the prevalence of vitamin D deciency and its associated risk factors among rural population in Bushehr province which has the longest border with the Persian Gulf. Materials And Methods Community sampling: Bushehr province which is located in the northern part of the Persian Gulf, was divided in three geographical (the northern, the central, and the southern) parts. Each geographical part was then divided into three mountainous, plain, and seashore areas in order to assess the effect of latitude, dietary habits, and socio-economic status of inhabitants on their serum vitamin D levels. The sample size of each part was proportional to the size of each population. The household was selected as the sampling unit which were randomly selected systematically using census data. A total of 1806 rural inhabitants with ≥ 25 years old were selected. The exclusion criteria included being non-native, inability to give blood sample, disability to answer the questions, and being less than 25 years old. The participants completed a questionnaire including their anthropometric, demographic data, past medical history,